ref: 3b7e03a30ed29ee0666c00568bf67b8179c28d12
dir: /sys/src/cmd/eqn/over.c/
#include "e.h"
void boverb(int p1, int p2)
{
int treg;
double h, b, d, d1, d2;
extern double Overgap, Overwid, Overline;
treg = salloc();
yyval = p1;
d = EM(Overgap, ps);
h = eht[p1] + eht[p2] + d;
b = eht[p2] - d;
dprintf(".\tS%d <- %d over %d; b=%g, h=%g\n",
yyval, p1, p2, b, h);
nrwid(p1, ps, p1);
nrwid(p2, ps, p2);
printf(".nr %d \\n(%d\n", treg, p1);
printf(".if \\n(%d>\\n(%d .nr %d \\n(%d\n", p2, treg, treg, p2);
printf(".nr %d \\n(%d+%gm\n", treg, treg, Overwid);
d2 = eht[p2]-ebase[p2]-d; /* denom */
printf(".ds %d \\v'%gm'\\h'\\n(%du-\\n(%du/2u'\\*(%d\\v'%gm'\\\n",
yyval, REL(d2,ps), treg, p2, p2, REL(-d2,ps));
d1 = 2 * d + ebase[p1]; /* num */
printf("\\h'-\\n(%du-\\n(%du/2u'\\v'%gm'\\*(%d\\v'%gm'\\\n",
p2, p1, REL(-d1,ps), p1, REL(d1,ps));
printf("\\h'-\\n(%du-\\n(%du/2u+%gm'\\v'%gm'\\l'\\n(%du-%gm'\\h'%gm'\\v'%gm'\n",
treg, p1, Overline, REL(-d,ps),
treg, 2*Overline, Overline, REL(d,ps));
ebase[yyval] = b;
eht[yyval] = h;
lfont[yyval] = rfont[yyval] = 0;
sfree(p2);
sfree(treg);
}